April 23, 2014

24.03.11: Comet Elenin: A Great Show, But No Need for Bruce Willis.

The path of Comet Elenin through the inner solar system. (Created using the NASA/JPL Ephemeris Generator).

There’s a scene in the otherwise fairly decent 1990’s disaster flick Deep Impact where the President played by Morgan Freeman reveals that a cover-up has been ongoing for about a year to keep an impending inbound doomsday comet a secret. Such drama makes most backyard observers chuckle inside; we know that on any given night, legions of observers are looking skyward, hoping to find a body that could immortalize our efforts. By day and on cloudy evenings, we’re at our keyboards, sharing data and computing orbits. Our tools are homemade observatories, sometimes housing instruments that would make some universities blush. It’s extremely unlikely that the “Big One” would slip by the worldwide astronomical community. That’s why I got a brief chortle this morning out of a message board post suggesting that one only need conduct a brief (insert favorite search engine here) scouting of the ‘Net for C/2010 X1 Elenin. The name was familiar to me and observers everywhere; This comet may put on the summer’s best show of the year as it passes perihelion on September 10th at 0.45 A.U. from the Sun and moves into the predawn sky, well positioned for northern hemisphere viewers. Then, in October, Elenin will pass within 0.3 A.U. (about 28 million miles, or 112 lunar distances) from the Earth… Yes, Elenin will probably put on a fairly decent show. One key indicator for this is that it was first spied about 4 A.U. from the Sun; this means that it’s fairly large and intrinsically bright, much like Hale-Bopp. The geometry of the pass is also very similar to the passage of comet McNaught in 2007, which means we may be in for a decent show as Elenin unfurls its dust tail on its way out of the inner solar system. But let’s just dispel some of the gathering Woo out there and state that there is ZERO chance that Elenin will impact the Earth. This is just one cosmic cat that even the likes of Morgan Freeman couldn’t keep in the bag. And no, myself and the legions of astronomers behind me are NOT in cahoots with Big Brother in hushing things up, as we have yet to receive one single pay off, and do our debunking on a pro bono basis.  And, much like comet Halley in 1910, Elenin will unfurl its tail in our direction, but remember, a cometary tail is mostly composed of… nothing! We’re talking a vacuum many orders of magnitude better than what can be done in a laboratory. Yes, nasties such as cyanide have been detected in the spectra of comets, but we aren’t due for a cyanogen bath this summer. Will Elenin sprout the hysteria seen in 1910? You’d think we’d have learned in a centuries time… but as Mark Twain once said, “A lie can travel ‘round the world while the truth is just puttin’ on its shoes…” and that paradigm is never more true than in today’s wired-in world. At very least, “Comet Pills” may be only an E-bay order away this time…

 

12.03.11: Attack (on the) Cyanobacteria?

Our x1023 Grandparents? (Credit: Richard B. Hoover, MSFC, Journal of Cosmology). 

This sunny weekend, we’d like to give some thought to the news story that erupted last weekend. Unless you’ve been off world, you’ve no doubt heard that researcher Richard B. Hoover of NASA’s/Marshall Space Flight Center released a paper via the Journal of Cosmology indicating the possible presence of fossilized cyanobacteria in certain types of carbonaceous meteorites. [Read more...]

15.02.11: New Views of Comet Tempel 1 Courtesy of StardustNExT.

A waxing gibbous cometary nucleus…(Credit: NASA/JPL/CalTech).

The re-designated StardustNExT spacecraft performed another first this Valentine’s Day, completing the first ever follow-up encounter of comet Tempel 1. [Read more...]

19.01.11: A Valentine’s Day Flyby.

The view of Comet Tempel-1 as seen from Deep impact in July 2005; this year’s visit plans to be friendlier… (Credit:NASA-JPL-Caltech-UMD).

One down, and one to go… next month, NASA intends to perform another first; the first follow up flyby of a cometary nucleus. The spacecraft is Stardust, and the comet is Tempel 1. Today’s mission briefing gave a glimpse of the action that is in store. Launched in February, 1999 Stardust has performed an array of firsts, including the first sample return from Comet Wild 2 in 2004, and one of the highest re-entry velocities ever attempted during its successful sample return in 2006. [Read more...]

AstroEvent:The Ursa Minorids; a Meteor Shower in the Making?

A new radiant? (Created by the author in Starry Night).

The general impression that most folks have of annual meteor showers is that they are largely static in nature. Long term trends, however, would suggest that they are slowly evolving, with new streams of debris replacing faint exhausted ones. Did our prehistoric ancestors watch the Perseids every August? Are there historically unknown meteor streams out there? What’s the life span on the average shower? This week, we give you what could be a meteor shower in the making; the Gamma Ursae Minorids. [Read more...]

Near Earth Objects: Mitigating the Threat.

(Editor’s Note: What follows is a scenario/article along with an original lesson plan re-written for a blog format).

Arizona Meteor Crater… x100=a bad day for the Earth? (Photo by Author).

Eventually, it had to happen. With scant warning, the announcement is made that a large space rock is inbound to strike Earth and is only weeks away. The news largely takes the public by surprise; this is the big one, an extinction class event. People are exasperated to learn that little can be done to deflect the large impactor; all that remains is for scientists to predict the precise impact location and for world organizations to attempt evacuations so that some of humanity might survive… [Read more...]

AstroEvent: A Bright Dawn Comet.

 

Created with NASA/JPL Ephemeris generator).

Created with NASA/JPL Ephemeris generator).

 

   The dawn skies of October hold a special treat; a possible bright morning comet. 103/P Hartley 2 approaches perihelion on October 28, 2010. Earlier in the month sees it beginning its long dive through dawn skies. Northern hemisphere viewers will have the best view, as the comet passes through the constellations Cassiopeia, Perseus, Auriga, and Gemini in the month of October. [Read more...]

09.05.10: First Re-Visit of a Comet in the Works.

(Credit: NASA/JPL).

(Credit: NASA/JPL).

An artists’ impression of Stardust NExT at comet Temple 1.

  NASA engineers directed the Stardust spacecraft to fire its rockets briefly on the of 17th of February, putting it on course for a new mission; a flyby of comet Tempel 1 February 14th of next year. If that comet sounds familiar, it should be; Tempel 1 was smacked by an impactor released from the Deep Impact space probe in 2005. The pass will allow scientists to see how the impact crater has evolved, as well as mark the first mission to re-visit a comet. Launched on February 7th, 1999, Stardust also returned a first ever sample of a comet. This sample has been the subject of much scrutiny by Earth-bound scientists, including that favorite obsessive/compulsive-creating crowd-sourcing project, Stardust@home. Hey, I’m still in the top 100, last time I checked…  NASA has also rechristened the spacecraft as Stardust NExT, or the New Exploration of Tempel. Not only will next years’ passage provide close-ups of the nucleus, but expect to see high resolution images of the coma and key insight into just how these Jupiter-class family of comets formed and evolved.

22.04.10-The Exotic World of Prometheus.

(Credit: NASA/ESA/Cassini).

(Credit: NASA/ESA/Cassini).

 The tiny shepherd world of Prometheus.

    The moons of Saturn continue to astound. The count now stands at 61, and one by one, NASA’s Cassini orbiter is giving us a close up look at these unique worlds, some for the first time. Last year, Cassini passed within 36,000 miles of Prometheus just the day after Christmas. Discovered by Voyager 1 in 1980, this shepherd moon dips within the F-ring once every 15 hour orbit. This fact is apparent as the oblong cratered surface on the 74 mile long moon is coated with a fine layer of dust, giving it a smooth appearance. The constant “plowing” of these moons through Saturn’s rings cause the grooves that we see, and also confines the F-ring. These images are especially satisfying to Carolyn Porco, lead scientist of the Cassini research team who was also on hand for the tiny moon’s initial discovery by Voyager in 1980. It’s likely that we won’t get another look at this bizarre shepherd moon for some years to come!

20.04.10: Hubble Smashes KBO record.

 

(Credit: "Drink Beer!").

(Credit: "Drink Beer!").

 The Structure of the Kuiper Belt.

   The Hubble Space Telescope has shattered yet another record; the smallest Kuiper Belt Object yet recorded. But the discovery came not from the telescope’s main optical array, but an unlikely source; its Fine Guidance Sensors. These star trackers point the HST and sample target stars 40 times a second. Using an innovative technique, a team led by Hike Schlichting sifted through 4.5 years of data to find a single 0.3 second in duration event. This is estimated to be a tiny KBO inclined about 14° degrees to the solar ecliptic. At an estimated 975 meters across and 6.8 billion kilometers distant, this object stands as the tiniest distant object ever detected. The Kuiper belt is a ring of icy material extending just beyond the orbit of Neptune out to about 55 astronomical units. At an estimated +35 magnitude in brightness, this icy body is far too small for even Hubble to see. The object was inferred indirectly by what’s known as a stellar occultation. This discovery also highlights the utility of pouring over the backlog of astronomical data generated by such platforms as Hubble. What other discoveries lay hidden it that thar’ data?

13.04.10- Mammoth Extinction vs. Impact Theory.

Woolly Mammoths: hunted to extinction?

  

   An Ice Age extinction mystery has just got more complicated. North America used to be home to some amazing mega-animal life, including wooly mammoths, saber-toothed cats the size of grizzly bears, and armadillos the size of Volkswagens. Then, around the time period known as the Younger Dryas about 12,900 years ago, a mass continent-wide extinction event occurred. Key theories include massive climate change, a large cometary impact, and that greatest of all predators, man. Now, research by Jacuelyn Gill of the University of Wisconsin has dealt a blow (pun intended) to the cometary impact hypothesis. Key evidence for a large airburst over the Laurentide ice sheet comes in the form of an iridium layer seen in the sedimentary deposits laid down at the time, as well as the discovery of minuscule nano-diamonds generated by the heat and blast of the explosion. The problem is, Gill’s studies of fungus spores found in fossilized dung finds the extinction event was already underway well before the impact, around 14,000 years ago. In addition, a mastodon skeleton in the Cincinnati museum has been found to have been dated from circa 10,055 years ago, well after the impact! This seems to put the appearance of Clovis man and overhunting as the key to large mammal extinction in the Ice Age North American scene. Perhaps even a combination of the factors was the cause. The concept of the Early Dryas extinction is unique because it is the most recent extinction event (other than the one we’re currently undergoing!) along a timeline of multiple events throughout the history of life on Earth. Being the most recent, perhaps more evidence for complicating factors is simply lying around for us to find. This debate is thus the hottest topic of all large extinction events. And one has to wonder; what would life in modern U.S. suburbia and camping trips be like if there were still saber-toothed cats around?

Event: Mars passes the Beehive.

 

The path of Mars over the coming week. (Created in Starry Night & Paint).

The path of Mars over the coming week. (Created in Starry Night & Paint).

  

    This week offers a two-fer, an easy to spot naked eye conjunction of two very different objects and a difficult to observe occultation. 1st up is a close pairing of the planet Mars and M44, the Beehive Cluster. From the 13th of April until the 20th, both will be grouped in a visual circle less than 2° arc degrees in diameter, an easy target for both camera lens or binocs. Mars will be at closest apparent approach on the evening of the 16th. Both ride high near the zenith in the dusk skies for northern hemisphere viewers, making for an easy photo op. Of course, Mars is a scant 3 odd light minutes away; M44 is at an estimated distance of 577 light years. Also known as Praesepe, the Manger, this cluster in the heart of the constellation Cancer has been known since ancient times. Proper motion studies suggest that this open cluster may share its origins with the V-shaped Hyades in the constellation Taurus; about 1010 members of this group have been identified, including 11 white dwarfs.

Up for a challenge? On the evening of the 15th, the 3 day old crescent Moon will occult the close spectroscopic binary star Mu (µ) Arietis.  The action occurs around 3:00 UT (on the 16th) and favors viewers on the North American west coast. Unfortunately, the event does not occur under the most favorable circumstances; the Moon will be a thin crescent, the star is +6 magnitude, and the entire event will be low in the dusk skies. Still, we’d love to hear from anyone who successfully witnessed this difficult to observe event!      

The astro-word for the week is Messier Object. Back in 1771, French astronomer Charles Messier got tired of misidentifying faint little fuzzies he came across in the night sky in his quest for comets and decided to compose a catalog of these objects. The original published list contained 45 objects and Messier later expanded it to 103. The current tally stands at 110, although the list contains a few dubious entries. The catalog was the first list of deep sky objects, and has since spurred countless “Messier Marathons” common in spring. Morphologically, the catalog contains open & globular clusters, planetary nebulae, emission nebulae and galaxies. Of course, Messier had no inkling what these objects truly were when he cataloged them. It’s somewhat odd that such un-comet like objects as M44 and the Pleiades made this list, but say, the Double Cluster on the Perseus-Cassiopeia border did not. And of course, there was a whole menagerie southern sky objects yet to be categorized. That would have to wait for the Herschel dynasty of astronomers, and their expanded New General Catalog!

11.04.10- Pale Blue Crescent.

 

(Credit: ESA/OSIRIS).

(Credit: ESA/OSIRIS).

 Earth as seen from Rosetta.

   It has been said innumerable times that in traveling into space, we’ve discovered the Earth. The Rosetta spacecraft reminded us what a unique place our home is on its trajectory altering flyby on November 13th of last year. Pictured above, you can easily tell that Earth is not a stagnant world, but a dynamic place, a place where interesting things are constantly happening. When the first astronomers looked at other planets in our solar system, it was thought that these worlds might not be any more hostile than, say, Antarctica. This concept still pervades some of the more campier of science fiction worlds, even today. But our explorations of the solar system have shown us something different, that even, say, a balmy day on Mars is magnitudes more hostile than Earth’s Gobi desert.

The European Space Agencies’ Rosetta spacecraft continues that spirit of exploration. Launched in 2004, it has performed a complex series of orbital slingshots that will cause it to eventually arrive at comet 67P/Churyumov-Gerasimenko in May 2014. There, it’ll take measurements of the icy interloper and even deposit a lander on the surface of a comet for the first time. Last year’s passage was Rosetta’s third and last flyby of its home world. The spacecraft had just passed asteroid 2867 Steins the year before, and is slated to perform a reconnaissance of asteroid 21 Lutetia in July of this year. The close passage with Earth gave it a 2.2 mile per second kick towards its final objective.

Do give pictures like those sent back by Rosetta pause, as we are the first and truly privileged generation to see our home world not as we’d like to see it, but as it actually is. Hey, we’re all on this Big Blue Marble together… perhaps we can get jaded by anything in time, but sights like these give us hope for our  survival as a species!

04.03.10- The Edgar Wilson Award: A Look at Last Year’s Winners.

One of the Wilson Awards more illustrious winners...(Credit: IAU Central Bureau for Astronomical Telegrams).

One of the Wilson Awards more illustrious winners...(Credit: IAU Central Bureau for Astronomical Telegrams).

 

   In this age of astronomical automation and ever increasingly deeper sky surveys, many believe the era of the amateur comet discoveries to be over. A look at last year’s Edgar Wilson Award winners, however, tells a different tale. Established in 1998, this award has historically split a $20,000 purse among 2 to 6 individuals who have discovered a comet in an amateur capacity. [Read more...]

08.11.09:Does Cometary Mass Extinction Need to be Rewritten?

The disconnection event of comet 73P Schwassmann-Wachmann-3 as seen from the Hubble Space Telescope. (Credit: NASA/ESA/H. Weaver STScl.)

The disconnection event of comet 73P Schwassmann-Wachmann-3 as seen from the Hubble Space Telescope. (Credit: NASA/ESA/H. Weaver STScl.)

Comets are cause all mass extinctions in Earth’s history, right? Maybe not, if new research is correct. Simulations run by the scientists at the University of Washington now suggest that the giant planets of Jupiter and Saturn may do a much more through job of cleaning up incoming debris than is generally realized. Short period comets such as Halley’s are generally accepted to be denizens of the Kuiper belt, which extends out to 100 Astronomical Units (A.U.s), while much more numerous populations of long period comets are theorized to come from the Oort cloud, a massive solar system-engulfing sphere at a distance of 1,000 A.U. to up to 3 light years distant. Traditional cometary mass extinction theory states that when a star passes close enough to the shell of the Oort cloud, a rain of comets are pried free and the inner solar system becomes a celestial shooting gallery for a million years or so. Simulations, however, suggest no more than three impacts could have occurred over the last 500 million years or so, fuel for at best maybe a minor extinction event or two. Then there’s the pesky affair of some extinct species shown to exist above the K-T iridium layer… doubtless, the case of mass extinction is a thoroughly messy business. As reported earlier last month in this space, more than one impactor is suspected in the extinction of the dinosaurs. Examination of other inner solar system bodies should pin down the frequency, duration, and average number of killer comets, as the Moon, Mars and even Mercury have relatively little erosion and would be potential targets as well. Any incoming comet stands a 40% chance of having its orbit altered by Jupiter, as happened to Hale-Bopp in the late 90′s. Thanks, Jove!

27.10.09: Exploring Shiva Crater.

A profile of Shiva Crater. (Credit: Sankar Chatterjee/Texas Tech University).

A profile of Shiva Crater. (Credit: Sankar Chatterjee/Texas Tech University).

Move over, Chicxulub; we may have a new contender in the realm of cosmic extinction events. Recently, paleontologist Sankar Chatterjee of Texas Tech University has dubbed a ring shaped subsurface structure off of the western coast of India Shiva crater. If Chaterjee is correct, it would be one of the largest impact basins on Earth recorded, at a diameter of about 500 km wide. Aptly named after the Hindu goddess of destruction, Shiva would have been caused by an asteroid or comet of about 40 km in diameter. Chaterjee has been following data accrued by decades of off-shore oil drilling projects in the area; the existence of iridium deposits suggests a calamity of cosmic origin. Rare on Earth but common on asteroids, the element iridium was considered a “smoking gun” in dating the aforementioned K-T extinction event of about 65 million years ago. Tantalizingly, the Shiva Crater event also seems to date from the same era. This raises the question; could a hail of cometary debris have been common in that far gone time? Bodies without rapid erosion, such as our Moon or Mars, should show evidence of impacts dating from around this epoch. Of course, the crater hypothesis is not without its critics…the area surrounding the Indian subcontinent is very geologically active as it pushes under the plates of the Asian continent. In particular, an area known as the Deccan Traps extends to the edge of Shiva and was very active during the Cretaceous period. Also, Shiva appears to have rock from the Earth’s underlining mantle exposed, again tantalizing evidence for a past cataclysm… this area of our own near space begs for further exploration!

AstroEvent of the Week: 13.04.09: New Comet Yi-SWAN!

Yi-SWAN.

The Path of Comet Yi-Swan from April 11th to May 11th. (Created in Starry Night).

We interrupt our usual astro-event of the week to bring you a last minute shout-out a tad early; a fairly bright comet has recently been announced by the Central Bureau of Astronomical Telegrams (CBAT) in Cambridge, Massachusetts (really; does anyone actually send telegrams any more? Time to change the name, guys!) Dubbed Yi-SWAN after its co-discovers, Korean amateur Dae-am Yi who sighted the comet on March 26th and the European Space (ESA)’s SWAN, the Solar Wind Anisotropies satellite, Comet Yi Swan is expected to maintain around 8th magnitude for the next month or  so. [Read more...]

Astro-Event of the Week, August 5th-11th, 2008: The Perseid Meteors!

   August always meant one thing for me as a kid; the Perseid Meteor shower . Arguably one of the  best, or at least most dependable meteor showers of the year, this shower also has the advantage of occurring in the middle of the northern hemisphere summer, when conditions are conducive to laying out under the stars for long stretches of time. [Read more...]